React-Native Android ReactContext returning null -

as react-native appstate api ios i'm writing appstate event emitter android side of app. in app's mainactivity on java side, want emit onresume , onpause functions tell js side on bridge app either in foreground or background

at moment, can minimise app (and go home-screen on device) , background event emitted correctly. however, when resume app nothing fired...also nothing fired when app opens up.

i've narrowed down fact in these cases mreactinstancemanager.getcurrentreactcontext() null...for reason.

here's code mainactivity.java:

@override protected void onpause() {     super.onpause();      if (mreactinstancemanager != null) {         mreactinstancemanager.onpause();          //send appstate js         log.d("react_state", "paused");  //this fires         if(mreactinstancemanager.getcurrentreactcontext()!=null) {             writablemap params = arguments.createmap();             params.putstring("currentappstate", "background");             sendevent(mreactinstancemanager.getcurrentreactcontext(), "appstatechange", params);         }     } } 

and,

@override protected void onresume() {     super.onresume();      if (mreactinstancemanager != null) {         mreactinstancemanager.onresume(this, this);          //send appstate js         log.d("react_state", "resumed"); //this fires         if(mreactinstancemanager.getcurrentreactcontext()!=null) {             writablemap params = arguments.createmap();             params.putstring("currentappstate", "foreground");             sendevent(mreactinstancemanager.getcurrentreactcontext(), "appstatechange", params);         }     } } 

and emitter code:

private void sendevent(reactcontext reactcontext,                        string eventname,                        @nullable writablemap params) {     reactcontext             .getjsmodule(deviceeventmanagermodule.rctdeviceeventemitter.class)             .emit(eventname, params); } 

the js side of things set ok , working - can provide code if helps. i'm issue lies on side. trying emit @ wrong time? need move elsewhere? advice appreciated!

ok, i've managed sort this. created new plugin package appstateandroid emits js. added @ right time in app lifecycle , works perfectly. i'm going post code github (http://github.com/scgough) that's wondering here go:

public class appstateandroidplugin extends reactcontextbasejavamodule implements application.activitylifecyclecallbacks {  private static final string plugin_name = "appstateandroid";  private reactcontext mreactcontext;  protected activity activity = null;  protected activity getactivity(){     return this.activity; }  public appstateandroidplugin(reactapplicationcontext reactcontext, activity activity) {     super(reactcontext);      this.mreactcontext = reactcontext;      this.activity = activity;     this.activity.getapplication().registeractivitylifecyclecallbacks(this); }  private void sendevent(reactcontext reactcontext,                        string eventname,                        @nullable writablemap params) {      log.d(plugin_name, "sending event"+params.tostring());     reactcontext             .getjsmodule(deviceeventmanagermodule.rctdeviceeventemitter.class)             .emit(eventname, params); } ... @override public void onactivityresumed(activity activity) {     log.d(plugin_name, "resumed");     if(mreactcontext!=null) {         writablemap params = arguments.createmap();         params.putstring("currentappstate", "active");         sendevent(mreactcontext, "appstatechange", params);     } }  @override public void onactivitypaused(activity activity) {     log.d(plugin_name, "paused");     if(mreactcontext!=null) {         writablemap params = arguments.createmap();         params.putstring("currentappstate", "background");         sendevent(mreactcontext, "appstatechange", params);     } } ... @override public void onactivitydestroyed(activity activity) {     activity myactivity = this.getactivity();     if (activity == myactivity){         myactivity.getapplication().unregisteractivitylifecyclecallbacks(this);     } }  @override public string getname() {     return plugin_name; } } 

you'll need package file in main activity:

mreactinstancemanager = reactinstancemanager.builder()             .setapplication(getapplication())             .setbundleassetname("index.android.bundle")             .setjsmainmodulename("index.android")             .addpackage(new mainreactpackage())             .addpackage(new appstateandroidpluginpackage(this))             ...